Narrow Results

We investigate the average-case speed and scalability of parallel algorithms executing on multiprocessors. Our performance metrics are average-speed and isospeed scalability. For the purpose of average-case performance prediction, we formally define the concepts of average-case average-speed and average-case isospeed scalability. By modeling parallel algorithms on multiprocessors using task precedence graphs, we are mainly interested in the effects of synchronization overhead and load imbalance on the performance of parallel computations. Thus, we focus on the structures of parallel computations, whose inherent sequential parts are limitations to high performance. Task execution times are treated as random variables, so that we can analyze the average-case performance of parallel computations. For several typical classes of task graphs, including iterative computations, search trees, partitioning algorithms, and diamond dags, we derive the growth rate of the number of tasks as well as isospeed scalability in keeping constant average-speed. In addition to analytical results, extensive numerical data are also demonstrated. An important discovery of our study is that while a parallel computation can be made scalable by increasing the problem size together with the system size, it is actually the amount of parallelism that should scale up with the system size. We also argue that under our probabilistic model of parallel algorithms and the list scheduling strategy, the number of tasks should grow at least at the rate of Θ(P log P), where P is the number of processors, so that a constant average-speed can be maintained. Furthermore, Θ(log P/ log P') is the highest isospeed scalability achievable.

An important research area in physiological and sport sciences is the analysis of the variations of the muscle reaction due to changes in walking speed. In this paper, we investigated the effect of walking speed variations on leg muscle reaction by the analysis of Electromyogram (EMG) signals at different walking inclines. For this purpose, we benefited from fractal theory and sample entropy to analyze how the complexity of EMG signals changes at different walking speeds. According to the results, although fractal theory could not show a clear trend between the variations of the complexity of EMG signals and the variations of the walking speed, however, based on the results, increasing the speed of walking in the case of different inclines is mapped on to the decrement of the sample entropy of EMG signals. Therefore, sample entropy could decode the effect of walking speed on the reaction of leg muscle. This analysis method could be applied to analyze the variations of other physiological signals of humans durin walking.

The next generation of wireless system is expected to provide multimedia, multi class services any time anywhere with seamless mobility and Quality of Service (QoS). In such environment, vertical handoff management plays an important and challenging role. Some of the main functions of vertical handoff management are: to implement appropriate vertical handoff decision to minimize number of unnecessary handoff, to maintain minimum vertical handoff latency for seamless mobility and to provide guaranteed acceptable QoS required for user satisfaction. Thus, in this paper to avoid unnecessary handoff in integrated heterogeneous network we have proposed that the vertical handoff decision depends on coverage area of the network and the speed of the Mobile Node. Application specific cut-off speed for particular coverage range of network during which handoff is beneficial has been determined. Real time applications like HDTV, MPEG-4, and H.261 are considered in integrated heterogeneous network of UMTS (Universal Mobile Telecommunication System) and WLAN. Vertical handoff latency is analyzed for varied network traffic load, types of application and varied speed of Mobile Node. Effect of Mobile Node speed on packet loss is also analyzed. Finally, to satisfy user with acceptable end to end QoS, especially in the presence of heterogeneous integrated networks where every network has individual QoS, an end to end QoS mapping scheme between UMTS and WLAN integrated network has been proposed. The simulation is performed using Network Simulator NS-2 with NIST (National Institute of Standards and Technology) add on module.

It has been proposed, particularly in connection with dyslexia and schizophrenia, that motion perception can be used to assess magnocellular integrity. This suggestion is examined in this paper. The following observations are made: (1) motion information, i.e., information about direction and speed, is extracted at the cortical level, (2) the magnocellular system provides input to the motion selective cortical entities, and (3) so do the parvo- and koniocellular systems. Therefore, although the magnocellular system clearly has the ability to influence motion perception so do other parts of the visual system, e.g., cortical mechanisms. It is concluded that motion perception by itself is not a reliable test of magnocellular integrity.

Extending the single optimized spaced seed of PatternHunter²⁰ to multiple ones, PatternHunter II simultaneously remedies the lack of sensitivity of Blastn and the lack of speed of Smith–Waterman, for homology search. At Blastn speed, PatternHunter II approaches Smith–Waterman sensitivity, bringing homology search methodology research back to a full circle.

Our research examines the relationships among four factors thought to be important to new product developing organizations. Those factors include the speed with which product developers produce new products and bring them to market; the degree of integration among the various groups participating in the New Product Development (NPD) process; the proficiency with which the product developers perform their tasks; and the degree of success attained upon the completion of the NPD process. Market dynamism, or the degree of customer changeability, and market hostility, or the degree of market competitiveness, are thought to moderate the relationships among the four previously noted factors.

The research questions driving our investigation include: (1) Does NPD project success vary with NPD process speed?; (2) Does NPD speed vary across innovation types (new-to-the-world products, line extensions, etc.)?; (3) Does the strength of the relationships among NPD speed, organizational integration, NPD proficiency (overall and Fuzzy Front End [FFE]), and success vary with the degree of environmental dynamism (changing customer needs)?; and (4) Does the strength of the relationships among NPD speed, organizational integration, NPD proficiency (overall and FFE), and success vary with the degree of market hostility (competition)? We probed the electrical equipment, medical device, and heavy construction equipment industries to provide the data to address our research questions.

Our research suggests that the speed with which projects were completed in our sample did not vary between projects that were more or less successful. We also found that the speed with which projects were completed did not vary across various product categories (new-to-the-world, line extensions, etc.) of newly developed products for the industries studied. Primarily, we found that market dynamism moderates the relationship between NPD speed and NPD proficiency whereas environmental hostility mediates NPD speed and NPD proficiency, NPD speed and organizational integration, and NPD speed and new product market success.

Our data indicate that speed is not associated with NPD proficiency, degree of organizational integration, and new product success in less dynamic markets whereas speed has an inverse relationship with successfully entering new markets, the proficiency with which development and launch activities are performed, and the proficiency with which new product marketing strategies were implemented in more dynamic markets. Finally, we found that speed is inversely related to successfully entering new markets, overall NPD proficiency and organizational integration, predevelopment stage proficiency and organizational integration, and development and launch proficiency and organizational integration in non-hostile (competitive) environments whereas we found no significant relationships between these factors and speed in hostile environments. We provide several implications for both scholars and NPD managers.

Production of energy is a foundation of life. The metabolic rate of organisms (amount of energy produced per unit time) generally increases slower than organisms’ mass, which has important implications for life organization. This phenomenon, when considered across different taxa, is called interspecific allometric scaling. Its origin has puzzled scientists for many decades, and still is considered unknown. In this paper, we posit that natural selection, as determined by evolutionary pressures, leads to distribution of resources, and accordingly energy, within a food chain, which is optimal from the perspective of stability of the food chain, when each species has sufficient amount of resources for continuous reproduction, but not too much to jeopardize existence of other species. Metabolic allometric scaling (MAS) is then a quantitative representation of this optimal distribution. Taking locomotion and the primary mechanism for distribution of energy, we developed a biomechanical model to find energy expenditures, considering limb length, skeleton mass and speed. Using the interspecific allometric exponents for these three measures and substituting them into the locomotion-derived model for energy expenditure, we calculated allometric exponents for mammals, reptiles, fish, and birds, and compared these values with allometric exponents derived from experimental observations. The calculated allometric exponents were nearly identical to experimentally observed exponents for mammals, and very close for fish, reptiles and the basal metabolic rate (BMR) of birds. The main result of the study is that the MAS is a function of a mechanism of optimal energy distribution between the species of a food chain. This optimized sharing of common resources provides stability of a food chain for a given habitat and is guided by evolutionary pressures and natural selection.

The damage pattern observed during the 1819 Kutch earthquake and 2001 Bhuj earthquake of magnitude $\mathrm{\text{Mw}}>7.7$ in India implied the significance of the effect of Kutch basin on seismic ground motion. In the present study, the Kutch rift basin is modeled as a simplified rectangular basin of size 150km $\times$ 90km $\times$ 1.5km. The shear wave velocity of the Kutch region varies from 300m/s at the surface to 800m/s at the depth of 60m. Three-dimensional ground response analysis is carried out for the simplified Kutch basin subjected to ricker wave, using the spectral element code SPEED. The soil medium is modeled through visco-elastic soil model, where the damping is represented by Quality factor. It is found out from the numerical analysis that maximum amplification of 3.6 times occurs at the corner of the basin where interference of waves reflected from multiple edges happen. The long period structures with fundamental period in the range of 1.5–2.5s located near the basin edge are found to be significantly affected by the basin effect.

This paper describes the novel mathematical modeling of the 3-phase induction motor, various operations and study of its dynamic behavior and regenerative braking based on the model. This model uses v/f scheme to apply braking operation with the energy flow to the supply system instead of wasting the energy in braking resistor. It discusses the theory of induction motors, which is explored through both equations and computer simulation model using SIMULINK. The model also helps to study the behavior of the motor during its starting and load variation. The results from the analysis prove the demonstration of regenerative braking and the dynamic behavior and can give an opportunity to learn the different characteristics during these conditions.

Recently, there are more people jogging with a treadmill at the gym or the home setting. The main available selected modes for treadmill jogging are speed and slope of incline. Increased speeds and incline slopes will not only increase the cardiopulmonary loading but may also alter the lower extremity (LE) movement patterns. There are few systematic investigations of the effect of the speed and incline on LE kinematics. Most studies have used 2D methods which focused on movements in sagittal plane only and this has limitations in the acquired data since lower extremity movements also include frontal and transverse planes. The current study aimed to investigate LE movement during jogging at different speeds and incline slopes using a high speed three-dimensional (3D) motion analysis system.

Eighteen young healthy males were recruited. The video-based motion capture system with six CCD cameras, HIRES Expert Vision System (Motion Analysis Corporation, CA, USA), was used to collect kinematic data at a sampling frequency of 120Hz. Nineteen passive reflective markers were attached to bilateral lower extremities of the subject. The joint angle is calculated by Euler angle using the rotation sequence: 2-1-3 (y-x′-z″). Four speeds were selected: 2 m/s, 2.5 m/s, 3 m/s, 3.5 m/s with the slope at 0, and four slopes were selected: 0%, 5%,10%,15% at a speed of 3 m/s. Repeated-measures ANOVA was used to test hypotheses regarding changes in jogging condition on LE kinematic variables. The significance level was set at 0.05.

As the jogging slope increased, the hip, knee and ankle demonstrated a significantly greater maximum flexion in swing phase (p<0.001), but the maximum extension angles in stance phase were relatively unchanged. Increased LE flexion during swing phase is important to ensure foot clearance with increased slope. For increased speed, the hip and ankle joints had significantly greater maximum joint extension angles during stance phase and the hip and knee joint had significantly larger maximum flexion angles in swing phase (p<0.001). Increased motion during swing phase account for a larger step length and increased motion during stance phase may facilitate the generation of power during forward propulsion as the jogging speed increased. As the slope and speed increased, LE movement patterns were changed in the transverse plane: the significantly increased (p<0.01) internal hip rotation at terminal stance, the increased toe-in of foot (p<0.001) during terminal stance phase and decreased (p<0.05) toe-out during swing phase. Increased hip motion in transverse plane could lengthen the stride distance and increase foot toe-in for providing a stable lever for push off to increase propulsion force as speed or slope is increased. By way of systematic 3D kinematic investigation of the LE in jogging, the results further elucidate the effect of changing speed and incline on LE joints movements. This information could provide guidelines for rehabilitation clinicians or coaches to select an appropriate training mode for jogging.

Despite the growing popularity in recent years of elliptical exercise (EE), little is known regarding the loadings applied to the body during EE. Since overloading to the body may lead to early fatigue of the muscles and increase the incidence of overuse injuries, such information is necessary for safe use of the elliptical trainer (ET) as a fitness tool. The current study aimed to determine the typical patterns and loading rates of the measured pedal reaction forces (PRF), and to quantify their differences from those during level walking, and the effects of pedaling rate. Fifteen male adults performed level walking and EE while 3D marker data, right PRFs and ground reaction forces (GRF) were measured. The parameters of the ET were set for two different pedal rates: 50 rpm and 70 rpm. For each pedal rate, the parameters were set to match the variables measured during level walking, with a mean step length of 55% leg length and no workload. During early stance the vertical PRF was smaller than the GRF, while the medial and posterior PRF were greater. PRFs also occurred during swing. Loading rates around heelstrike during EE were all smaller than those during walking. The medial, anterior and posterior PRF, as well as the medial and vertial loading rates increased with increasing pedal rates. The basic force patterns of EE and the effects of pedal rate were established in order to determine the true potential for such instrumentation in locomotion analysis. The results will be helpful for future related studies.

Our research examines the relationships among four factors thought to be important to new product developing organizations. Those factors include the speed with which product developers produce new products and bring them to market; the degree of integration among the various groups participating in the New Product Development (NPD) process; the proficiency with which the product developers perform their tasks; and the degree of success attained upon the completion of the NPD process. Market dynamism, or the degree of customer changeability, and market hostility, or the degree of market competitiveness, are thought to moderate the relationships among the four previously noted factors.

The research questions driving our investigation include: (1) Does NPD project success vary with NPD process speed?; (2) Does NPD speed vary across innovation types (new-to-the-world products, line extensions, etc.)?; (3) Does the strength of the relationships among NPD speed, organizational integration, NPD proficiency (overall and Fuzzy Front End [FFE]), and success vary with the degree of environmental dynamism (changing customer needs)?; and (4) Does the strength of the relationships among NPD speed, organizational integration, NPD proficiency (overall and FFE), and success vary with the degree of market hostility (competition)? We probed the electrical equipment, medical device, and heavy construction equipment industries to provide the data to address our research questions.

Our research suggests that the speed with which projects were completed in our sample did not vary between projects that were more or less successful. We also found that the speed with which projects were completed did not vary across various product categories (new-to-the-world, line extensions, etc.) of newly developed products for the industries studied. Primarily, we found that market dynamism moderates the relationship between NPD speed and NPD proficiency whereas environmental hostility mediates NPD speed and NPD proficiency, NPD speed and organizational integration, and NPD speed and new product market success.

Our data indicate that speed is not associated with NPD proficiency, degree of organizational integration, and new product success in less dynamic markets whereas speed has an inverse relationship with successfully entering new markets, the proficiency with which development and launch activities are performed, and the proficiency with which new product marketing strategies were implemented in more dynamic markets. Finally, we found that speed is inversely related to successfully entering new markets, overall NPD proficiency and organizational integration, pre-development stage proficiency and organizational integration, and development and launch proficiency and organizational integration in non-hostile (competitive) environments whereas we found no significant relationships between these factors and speed in hostile environments. We provide several implications for both scholars and NPD managers.

Each rapid prototyping (RP) process has its special and unique advantages and disadvantages. The chapter presents a state-of-the-art study of RP technologies and classifies broadly all the different types of rapid prototyping methods. Subsequently, the fundamental principles and technological limitations of different methods of RP will be closely examined. Comparison of the present and ultimate performance of the rapid prototyping processes will be made so as to highlight the possibility of future improvements for a new generation of RP system.

This paper presents problem-solving strategies that Singapore students (n = 1002) used to solve three word problems on speed and the errors they made. It is surprising to find that the Primary 6 students performed significantly better than the Secondary 1 and Secondary 2 students, while the performance differences between the last two groups were not significant. The strategy analyses reveal that the Primary 6 students could use the arithmetic strategies, model method, and guess-and-check method more successfully than the secondary students. More effort needs to be made to bridge the gap between primary and secondary mathematics, and more word problems on speed need to be included in textbooks used in secondary levels.

Based on the classical control theory, this paper proposes an adjustable speed motor control model with minimum ripple effect. This feasibility study was conducted and simulated in Matlab using three typical input signals: the unit step, unit speed and acceleration. The simulation results shown that, the minimum ripple controller could ensure the speed of the electromagnetic speed control motor followed the expected speed in the shortest sampling cycle, to achieve the steady-state error of the system to zero. However, it only follows a particular input signal and therefore when the input signals vary, the controllers need to be calibrated separately to follow the signals, hence, with an electromagnetic adjustable speed motor, it is feasible to control a thin coal seam electrical traction shearer with minimum ripple effect.

In the current vessels is commonly used way of heaving line throwing outype, port type, rotary, centrifugal several, but every way heaving line is based on the power, speed is the core of speed strength of throwing project. The crew in the process of throwing by their own power to heaving line heads certain initial velocity. In this paper, through literature, survey, according to the theory of sports biomechanics, mechanics, sports anatomy for theory basis, combining the theory of track and field technique and related process of heaving line throwing discus throwing power points the swimmer is studied. Purpose is heaving line throwing theory; provide certain scientific basis for improving throwing distance.

The transfer part length of the pushing gauge shall be correspondingly increased with the increase of the paper format. According to the principle of tension degree and buffer length, the chain link number N of the laminating machine 1600 is determined. The drive system drawing is drawn through calculation and analysis of tooth number of each part of the laminating machine. Tooth number of each part is calculated through applying the method of continued fractions, and the original drive system drawing is then modified. Speed and correlation of each element are determined through comparison of the speed of laminating machine 1300 and laminating machine 1600.